The present invention relates generally to coated potato products and formulations and methods for coating potato products such as frozen french fries.
Methods for preparing and applying coatings to the outer surfaces of frozen potato products are well known in the art. Murray et al. U.S. Pat. No. 3,597,227 disclose a process in which raw potato strips are coated in a hot aqueous solution of modified gelatinized amylose derived from corn or potato starch. The process is said to produce a finished product which has superior strength and rigidity. Van Patten et al., U.S. Pat. No. 3,751,268 disclose the coating of blanched potato pieces with an ungelatinized unmodified high amylose starch having an amylose content of at least 50 percent. The coated potato strips are deep fat fried during which the starch in the coating is gelatinized.
El-Hag et al. U.S. Pat. No. 4,317,842 discloses the process of dipping blanched potato strips in an aqueous ungelatinized starch slurry to coat the strips, which are next soaked in hot oil to gelatinize the starch in the coating. The strips are then parfried and frozen. The strips may be reheated for consumption by heating in an oven rather than by deep fat frying.
Lenchin et al., WO 85/01188 disclose batters comprising the flour of high amylose corn hybrids for producing microwaveable pre-fried foodstuffs. The use of flours of high amylose corn hybrids is said to provide pre-fried foodstuffs with improved crispness after microwave cooking which otherwise tends to make such products soggy.
Sloan et al., U.S. Pat. Nos. 5,059,435 and 5,141,759 disclose a process for preparing frozen coated potatoes wherein raw potatoes are washed, cut, blanched and partially dehydrated. The cut potatoes are then coated with an aqueous starch slurry comprising 15 to 35% by weight modified ungelatinized potato starch, 2 to 10% by weight modified ungelatinized corn starch, 2 to 10% by weight rice flour and other optional ingredients. The coated potato strips are parfried in oil and then frozen. The frozen strips are prepared for consumption by either finish frying in hot oil, or heating in an oven. The starch coating is said to enhance the holding quality of the ready to consume product and to improve the acceptability of the finished product by increasing the crispness of the outer surface, and helping to maintain the tenderness of the interior of the cut potato. In particular, the potato starch and corn starch are said to contribute crispness to the coating, and because they are not gelatinized prior to the parfrying step they decrease clumping of the strips during processing. The rice flour is said to provide a desirable tenderness in the finished product.
The Sloan patents teach the use of potato starches which have been modified through known chemical cross-linking processes in order to minimize sticking or clumping of the strips during processing, and coat the potato strips evenly. The Sloan patents disclose as preferred an ungelatinized chemically modified potato starch (K-1010, Penford Corporation, Richland, Wash.) which is crosslinked with phosphorus oxychloride (POCl3) at an effective level of 980 ppm. (This starch is characterized by a Brabender Amylograph viscosity of 50-100 BU (xe2x80x9cBrabender unitsxe2x80x9d) when measured at a 9% starch solids concentration for 15 minutes at 95xc2x0 C.) A chemically modified ungelatinized cornstarch said to be preferred for use in conjunction with the above modified potato starch is said to be Flojel(copyright) 60 (National Starch and Chemical Corp., Bridgewater, N.J.) which is a hydrolyzed cornstarch said to contribute crispness to the coating and to produce an optimal result when present in the coating slurry at a concentration of between two and ten percent by weight.
Also of interest to the present application is the disclosure of co-owned U.S. Pat. No. 5,648,110 which discloses use of potato starches with selected crosslinking levels as preferred components of starch enrobing slurries. Specifically, the patent discloses that potato strips coated with an aqueous starch enrobing slurry having an as is solids content comprising not less than about 50% by weight of ungelatinized crosslinked potato starch characterized by a viscosity of from 200 to 1100 Brabender Units (BU) when measured at 9% solids concentration after 15 minutes at 95xc2x0 C. (which corresponds to a crosslinking level of from 550 to 900 ppm using POCl3) and from 10 to 25% by weight rice flour provide improved crispness and texture properties. Also of potential interest to the present application is U.S. Pat. No. 5,750,168 which is directed to starch enrobing slurries having a solids content comprising not less than 20% by weight ungelatinized crosslinked tapioca starch characterized by a crosslinking level of from 300 to 1000 ppm. The patent teaches the incorporation of rice flour as a component of the enrobing slurries at solids contents preferably ranging from 10% to 25%. Of further interest to the present invention is the disclosure of U.S. Pat. No. 5,897,898 which is directed to starch enrobing slurries having an as is solids content comprising at least 40% by weight of a hydrolyzed starch characterized by a DE of from 0.2 to 0.8.
Also of interest to the present application are the disclosures of Calder et al., U.S. Pat. No. 5,302,410 and Brusacker et al., U.S. Pat. No. 5,393,552 which relate to the use of hydrolyzed starch products such as dextrins and maltodextrins as components of aqueous enrobing slurries. Specifically, the patents disclose contacting blanched potato strips with an aqueous solution which contains from 3% to 12% by weight of a hydrolyzed starch product characterized by a DE less than 12 and preferably from about 2 to 10. The patents specifically disclose the use of maltodextrins having a DE of 6 and teach against the use of maltodextrins having DE values greater than 12 because such hydrolyzate products promote undesirable browning of the final product. The patents further teach that concentrations of the starch hydrolyzate products greater than 12% are undesirable because xe2x80x9cat higher concentrations the surface of the potato strips become slightly tacky upon finish frying which promotes undesirable clumping of the potato strips.xe2x80x9d
Of further interest to the present invention is the disclosure of Melvej, U.S. Pat. No. 5,431,944 which discloses a dry batter mix for french fries comprising from about 1.5% to about 9% by weight of a leavening agent and from about 5% to about 40% by weight of a starch blend comprising a high amylose starch, a starch, from about 1% to about 8% by weight dextrin wherein the weight percent in the batter mix is inversely related to the weight percent of the leavening agent, and about 0.1% to about 2% of a food gum. The specification teaches that the batter mix preferably includes about 2% to about 6%, by weight of dextrin and that the dextrin xe2x80x9cprovides a tender bite and in improved mouthfeel to the reconstituted food product.xe2x80x9d The patent further teaches that xe2x80x9c[t]he particular amount of dextrin included in the batter mix is inversely related to the amount of leavening agent present in the batter mix. Therefore, as the amount of leavening agent in the batter is increased, the amount of dextrin in the batter mix is decreased, and vice versa. The dextrin mitigates the effects of the leavening agent and provides a more tender crispness. However, if too much dextrin is included in the batter mix, the reconstituted food product has a greasy mouthfeel.xe2x80x9d (Col. 7, lines 18-30).
Of interest to the present invention are the disclosures of patents which relate to methods of applying starch coatings to potato strips in a dry form. Bengtsson et al., U.S. Pat. No. 4,272,553 discloses a coating process which includes applying a dry coating directly onto the surface of a vegetable such as a potato to be fried as a method of absorbing the water from the cut potato. The patent discloses that the coating may be formed from a variety of materials including wheat or other cereal flours, soy or other oil seed flours, natural or modified starches from various raw materials, potato granules, potato flakes and potato fibers. The patent teaches the steps of (1) cutting the vegetable, (2) applying the dry coating, (3) blanching the coated vegetable, and (4) parfrying the vegetable.
Shanbhag et al., U.S. Pat. Nos. 4,931,296 and 4,931,298 disclose alternative processes for preparation of french fried potatoes for reheating in microwave ovens. According to a first method potatoes are (1) cut, (2) blanched, (3) parfried, and (4) dust-coated with potato granules having 90-95% of its granules at U.S. 40 mesh and which include no more than 8 percent moisture. According to an alternative procedure, potatoes are (1) cut, (2) blanched, (3) dust-coated, and (4) then parfried.
Baisier et al., U.S. Pat. No. 5,279,840 discloses a method of producing reduced fat deep fried french fries comprising the steps of (1) cutting potatoes, (2) dust-coating the potatoes with a mixture of amylose and calcium ions such as in a calcium salt, (3) blanching the potatoes, and (4) parfrying the potatoes.
Also of interest to the present invention are methods known in the art for the electrostatic application of coating materials to the surface of food products. As one example, Wang, U.S. Pat. No. 6,054,154 discloses the use of an electrostatic coating apparatus to apply a food grade powder blend to a cooked, whole meat muscle product placed on an electrically grounded support in a coating chamber. Similarly, U.S. Pat. No. 5,520,942 discloses the use of an electrostatic coating system for the application of food additives mixed with supercritical fluid to products such as potato chips.
Despite the exhaustive quantity of research devoted to improving french fry coatings there remains a desire in the art to develop coating formulations that are inexpensive, readily applied and provide improved organoleptic qualities to the french fries.
The present invention provides improved methods for preparing a frozen potato product (french fry) with a film-like coating on the outer surface comprising the steps of: cutting the potatoes; blanching the potatoes; and coating the potatoes with a dry coating composition comprising at least 50% by weight dextrin and from 5% to 20% by weight of a hydrolyzed starch characterized by a DE of from 0.2 to 5. The dry coating composition may be applied by various means known to those of skill in the art including a rotating tumbler, a dry powder spray system, and an electrostatic spray system although the use of an electrostatic spray system is particularly preferred. The potato strips may be frozen prior to coating with the dry coating composition but are preferably frozen after coating. The dry coating compositions of the invention preferably comprise at least 60% and as much as 75% by weight or more dextrins. Dextrins useful for practice of the invention may be produced from any starch source including, but not limited to, corn, potato, wheat and tapioca.
The second component of the dry coating composition is a hydrolyzed starch which is present at a concentration of from 5% to 25% with a concentration of 15% being preferred. The hydrolyzed starch can be enzyme or acid thinned and can be a granular or pregelled starch but is preferably a pregelled starch which has been acid thinned. The hydrolyzed starch is characterized by a DE of from 0.2 to 5 but is preferably characterized by a DE of from 0.2 to 2 but is more preferably characterized by a DE of from 0.2 to 1.
Accordingly to one preferred aspect of the invention, a third component may be incorporated into the dry coating compositions of the invention which is a maltodextrin/glucose syrup solids characterized by a DE ranging from 15 to 25. (A starch hydrolyzate product is characterized as a maltodextrin if it has a DE of less than 20 while starch hydrolyzate product having a DE of 20 or greater is considered to be glucose syrup solids (also known as a xe2x80x9ccorn syrup solids.xe2x80x9d) The maltodextrin/glucose syrup solids component adds a crispy character which becomes more apparent at longer hold times and is preferably incorporated at a concentration of from 5% to 35%. The invention also provides coated potato products produced according to the above-described methods as well as the dry coating compositions themselves.
The methods of the present invention are particularly useful because they provide coated potato products with good organoleptic properties even when the coatings are applied as a thin dry powder at low coating pickup levels. While french fry coating compositions are typically be applied at pickup levels of 6% to 8% and higher to achieve satisfactory results, the dry coating compositions of the invention provide improved organoleptic properties to coated potato strips when applied at pickup levels of less than 4% by weight. According to one aspect of the invention, the dry coating compositions of the invention may be applied at coating pickup levels of less than 2% by weight and as low as from 0.2% and 1.0% by weight while still providing good crispness and other desirable organoleptic properties.
According to another aspect of the invention, it is found that the incorporation of an octenyl succinate modified starch into a dry or aqueous enrobing slurry coating composition for application to potato products (french fries) or other foods provides improvements in the organoleptic character of the coated product. Accordingly, the invention also presents improvements in methods of preparing a potato product with a film-like coating on the outer surface by coating the potato product with an aqueous enrobing slurry or dry coating composition, by incorporating an octenyl succinate modified starch into said aqueous enrobing slurry or dry coating composition. The invention also provides an aqueous enrobing slurry for preparing a potato product with a film-like coating comprising at least 50% by weight of a modified starch component including but not limited to a crosslinked starch or starch hydrolysis product including dextrins and an octenyl succinate modified starch, and a dry coating composition for preparing a potato product with a film-like coating comprising at least 50% by weight of a modified starch component including but not limited to a crosslinked starch or starch hydrolysis product including dextrins and an octenyl succinate modified starch.